Composite structures often include a laminate structure in which sheets of a composite material, such as a pre-impregnated (or prepreg) material, may be bent, wrapped, and/or otherwise extended between a first plane, or surface, and a second plane, or surface. The finite thickness and/or mechanical stiffness of the sheets of composite material result in a finite bend, or radius of curvature, in a transition region between the first surface and the second surface; and, in some geometries, this finite radius of curvature results in a void space, or cavity, between adjacent sheets of composite material.
This void space may be filled with, or otherwise occupied by, a filler material, such as a radius filler. The radius filler may be configured to provide mechanical support to the sheets of composite material that are proximal thereto and/or to decrease a potential for distortion of the sheets of composite material while the composite structure is curing. While the presence of the radius filler may provide a variety of benefits to the composite structure, differences between a geometry, cross-sectional shape, and/or material property of the radius filler when compared to a geometry, cross-sectional shape, and/or material property of the composite material that defines the void space may distort the composite structure and/or the radius filler during formation and/or curing of the composite structure. Thus, it may be desirable to closely match the shape of the radius filler to a shape, or a desired shape, of the void space. In addition, it also may be desirable to match the material properties of the radius filler to that of the sheets of composite material and/or the resultant composite structure.
Traditional radius fillers often utilize a single length of composite material that may be creased in a number of locations to form an accordion shape and then molded to a final desired shape. Alternatively, the traditional radius fillers may utilize a plurality of lengths of composite material that are stacked, one on top of the other, to form a plurality of parallel planes of composite material. Neither of these approaches permits tight control of the shape and/or material properties of the radius filler, let alone matching the shape and/or material properties to that of the surrounding layup. Thus, there exists a need for improved radius fillers for composite structures, as well as for improved systems and methods for fabricating the radius fillers.